This invention relates to attitude indicators and, more particularly, to an improved pitch servomechanism for use within an aircraft instrument utilizing an expanded scale to indicate attitude. In prior aircraft instruments, an indication of the pitch and roll of the aircraft is provided by a mechanical indicator in the form of a sphere having indicia on the surface thereof. The sphere in prior devices is capable of indicating a limited range of pitch due to stops which are necessary to keep the instrument synchronized. As a pilot seldom places his aircraft in a 90.degree. dive, or a 90.degree. climb, or flys it upside down, a limited indicating range presents no concern. With this in mind, aircraft instruments have been designed with an expanded scale in the .+-.30.degree. climb and dive range for greater accuracy. Prior art instruments have relied on a gear train to provide the desired expansion. That is, the electric motor which positions the spherical indicator is coupled to the sphere through a gear train having a gearing ratio of, for example, one and one-half to one.
When a gear train is used, it is necessary to provide stops to prevent the indicator from rotating 360.degree., since without stops the indicator loses synchronization after one rotation. The inclusion of a gear train and the necessary stops associated with it increase the size and weight of prior art indicators. Further, stops have a tendency to stress an indicator when the aircraft in which it is mounted undergoes abrupt changes in attitude.